Polyether ether ketone (PEEK) Properties & Applications

Polyether ether ketone (PEEK) is a colourless organic thermoplastic polymer in the polyaryletherketone (PAEK) family, used in engineering applications. It was originally introduced by Victrex PLC, then Imperial Chemical Industries (ICI) in the early 1980s.

Properties:PEEK is a semicrystalline thermoplastic with excellent mechanical and chemical resistance properties that are retained to high temperatures. The processing conditions used to mold PEEK can influence the crystallinity and hence the mechanical properties. The Young's modulus is 3.6 GPa and its tensile strength 90 to 100 MPa.[5] PEEK has a glass transition temperature of around 143 °C (289 °F) and melts around 343 °C (662 °F). Some grades have a useful operating temperature of up to 250 °C (482 °F). The thermal conductivity increases nearly linearly with temperature between room temperature and solidus temperature. It is highly resistant to thermal degradation, as well as to attack by both organic and aqueous environments. It is attacked by halogens and strong Bronsted and Lewis acids, as well as some halogenated compounds and aliphatic hydrocarbons at high temperatures. It is soluble in concentrated sulfuric acid at room temperature, although dissolution can take a very long time unless the polymer is in a form with a high surface-area-to-volume ratio, such as a fine powder or thin film. It has high resistance to biodegradation.

Applications:Because of its robustness, PEEK is used to fabricate items used in demanding applications, including bearings, piston parts, pumps, High-performance liquid chromatography columns, compressor plate valves, and electrical cable insulation. It is one of the few plastics compatible with ultra-high vacuum applications. PEEK is considered an advanced biomaterial used in medical implants, e.g., use with a high-resolution magnetic resonance imaging (MRI), for creating a partial replacement skull in neurosurgical applications.

PEEK is finding increased use in spinal fusion devices and reinforcing rods. It is extensively used in the aerospace, automotive, and chemical process industries. PEEK seals and manifolds are commonly used in fluid applications. PEEK also performs well in applications where continuous high temperatures (up to 500 °F/260 °C) are common.

Polymer adsorption

Adsorption is the adhesion of ions or molecules onto the surface of another phase.Adsorption may occur via physisorption and chemisorption. Ions and molecules can adsorb to many types of surfaces including polymer surfaces. A polymer is a large molecule composed of repeating subunits bound together by covalent bonds. The adsorption of ions and molecules to polymer surfaces plays a role in many applications including: biomedical, structural, and coatings.

Polymer surfaces differ from non-polymer surfaces in that the subunits that make up the surface are covalently bonded to one another. Non-polymer surfaces can be bound by ionic bonds, metallic bonds or intermolecular forces (IMFs). In a two component system, non-polymer surfaces form when a positive net amount of energy is required to break self-interactions and form non-self-interactions. Therefore, the energy of mixing is positive. This amount of energy, as described by interfacial tension, varies for different combinations of materials. However, with polymer surfaces, the subunits are covalently bonded together and the bulk phase of the solid surface does not allow for surface tension to be measured directly. The intermolecular forces between the large polymer molecules are difficult to calculate and cannot be determined as easily as non-polymer surface molecular interactions.[2] The covalently bonded subunits form a surface with differing properties as compared to non-polymer surfaces. Some examples of polymer surfaces include: polyvinyl chloride (PVC), nylon, polyethylene (PE), and polypropylene (PP). Polymer surfaces have been analyzed using a variety of techniques, including: scanning electron microscopy, scanning tunneling microscopy, and infrared spectroscopy.

Different polymer surfaces have different side chains on their monomers that can become charged due to the adsorption or dissociation of adsorbates. For example, polystyrene sulfonate has monomers containing negatively charged side chains which can adsorb positively charged adsorbates. Polystyrene sulfonate will adsorb more positively charged adsorbate than negatively charged. Conversely, for a polymer that contains positively charged side chains, such as poly(diallyldimethylammonium chloride), negatively charged adsorbates will be strongly attracted.

Structural

Advanced polymer composites:Advanced polymer composites are used in the strengthening and rehabilitation of old structures. These advanced composites can be made using many different methods including prepreg, resin, infusion, filament winding and pultrusion. Advanced polymer composites are used in many airplane structures and their largest market is in aerospace and defense.

Fiber reinforced polymers:Fiber-reinforced polymers (FRP) are commonly used by civil engineers in their structures. FRPs respond linear-elastically to axial stress, making them a great material to hold a load. FRPs are usually in a laminate formation with each lamina having unidirectional fibers, typically carbon or glass, embedded within a layer of light polymer matrix material. FRPs have great resistance against environmental exposure and great durability.

Polytetrafluoroethylene:Polytetrafluoroethylene (PTFE) is a polymer used in many applications including non-stick coatings, beauty products, and lubricants. PTFE is a hydrophobic molecule composed of carbon and fluorine. Carbon-fluorine bonds cause PTFE to be a low-friction material, conducive in high temperature environments and resistant to stress cracking. These properties cause PTFE to be non-reactive and used in a wide array of applications.

Polymer adsorption in porous media:Physical adsorption and mechanical entrapment are two major causes of polymer retention in porous media. Low polymer retention in the reservoir is essential to the success of a polymer EOR operation. 

ETFE vs PTFE

Ethylene tetrafluoroethylene (ETFE) is a fluorine-based plastic. It was designed to have high corrosion resistance and strength over a wide temperature range. ETFE is a polymer and its source-based name is poly(ethene-co-tetrafluoroethene). ETFE has a relatively high melting temperature, excellent chemical, electrical and high-energy radiation resistance properties. When burned, ETFE releases hydrofluoric acid.

Useful comparison tables of PTFE against FEP, PFA and ETFE can be found on DuPont's website, listing the mechanical, thermal, chemical, electrical, and vapour properties of each, side by side.

ETFE is effectively the high-strength version of the other three in this group, often featuring slightly diminished capacities in other fields by comparison.

Combustion of ETFE occurs in the same way as a number of other fluoropolymers, in terms of releasing hydrofluoric acid (HF). HF is extremely corrosive and toxic, and so appropriate caution must be exercised.

ETFE film is self-cleaning (due to its nonstick surface) and recyclable. It is prone to punctures by sharp edges and therefore mostly used for roofs. As a film for roofing it could be stretched (up to 3x) and still be taut if some variation in size occurs (due to thermal expansion, for example.) Employing heat welding, tears can be repaired with a patch or multiple sheets assembled into larger panels.

ETFE has an approximate tensile strength of 42 MPa (6100 psi), with a working temperature range of 89 K to 423 K (−185 °C to +150 °C or −300 °F to +300 °F).[3]

ETFE resins are resistant to ultraviolet light. An accelerated weathering test (comparable to 30 years’ exposure) produced almost no signs of film deterioration.

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Fluorinated ethylene propylene VS PTFE

Fluorinated ethylene propylene or FEP is a copolymer of hexafluoropropylene and tetrafluoroethylene. It differs from the PTFE (polytetrafluoroethylene) resins in that it is melt-processable using conventional injection molding and screw extrusion techniques. Fluorinated ethylene propylene was invented by DuPont and is sold under the brandname Teflon FEP. Other brandnames are Neoflon FEP from Daikin or Dyneon FEP from Dyneon/3M.

FEP is very similar in composition to the fluoropolymers PTFE (polytetrafluoroethylene) and PFA (perfluoroalkoxy polymer resin). FEP and PFA both share PTFE's useful properties of low friction and non-reactivity, but are more easily formable. FEP is softer than PTFE and melts at 260 °C; it is highly transparent and resistant to sunlight.

FEP is produced by free-radical polymerization of mixtures of tetrafluoroethylene and hexafluoropropylene. The mixture is biased to compensate for the relatively low reactivity of the propylene component. The process is typically initiated with peroxydisulfate, which homolyzes to generate sulfate radicals. Because FEP is poorly soluble in almost all solvents, the polymerization is conducted as an emulsion in water, often using a surfactant such as PFOS. The polymer contains about 5% of the propylene component.

Useful comparison tables of PTFE against FEP, PFA and ETFE can be found on DuPont's website, listing the mechanical, thermal, chemical, electrical and vapour properties of each, side by side.

In terms of corrosion resistance, FEP is the only other readily available fluoropolymer that can match PTFE's own resistance to caustic agents, as it is a pure carbon-fluorine structure and fully fluorinated.

Thermally, FEP stands out from PTFE and PFA by having a melting point of 260 °C (500 °F), around forty degrees lower than PFA and lower again than PTFE.

Electrically, PTFE, FEP and PFA have identical dielectric constants, but FEP's dielectric strength is only surpassed by PFA. However, while PFA has a similar dissipation factor to PTFE, FEP's dissipation is around six times that of PFA and EFTE (making it a more non-linear conductor of electrostatic fields).

Mechanically, FEP is slightly more flexible than PTFE. Perhaps surprisingly, it does not withstand repetitive folding as well as PTFE. It also features a higher coefficient of dynamic friction, is softer and has a slightly lower tensile strength than PTFE and PFA.

A noteworthy property of FEP is that it is vastly superior to PTFE in some coating applications involving exposure to detergents.

Ethylene tetrafluoroethylene (ETFE), in many ways, can be thought of as belonging to a different group, as it is essentially a high strength engineering version of the others featuring what are likely to be considered slightly diminished properties in the other fields when compared with PTFE, FEP and PFA.

PTFE Floss

The Environmental Working Group recommends against using dental floss made with PTFE. The group states that "Exposure to PFCs has been associated with kidney and testicular cancer, high cholesterol, abnormal thyroid hormone levels, pregnancy-induced hypertension and preeclampsia, obesity and low birth weight . . . . PFCs pollute water, are persistent in the environment and remain in the body for years. Leading manufacturers of PFCs have agreed to phase out some of these chemicals by the end of 2015, including PFOA, the most notorious, which used to be a key ingredient in making Teflon. Unfortunately, there’s no evidence that the chemicals that have replaced PFOA are much safer."

Dentists have been telling us for decades that the use of dental floss effectively removes plaque, a gel-like substance made of bacteria that forms on and between teeth, as well as below the gum line. It has been thought to be an important part of our dental hygiene routine because normal brushing doesn't remove all the the plaque. And if it is not removed, it hardens and can cause gingivitis or an inflammation of the gums. Eventually, gums begin to separate from the teeth, forming “pockets” that can become infected, ultimately destroying bone and resulting in tooth loss. Flossing disturbs the bacteria, stopping it before it can create plaque. Various studies have shown that, aside from tooth loss, gum disease is a big risk factor for Alzheimer’s and memory issues.

However, doubt has recently been cast on the usefulness of dental flossing to effectively remove plaque. A 2015 investigation by the news organization the Associated Press (AP) involved Freedom of Information requests to the US Department for Health and Human Services (HHS) asking for the research leading to its recommendation in favor of flossing. The HHS subsequently quietly dropped the advice, and Public Health England has also said that it will be reviewing its own guidance on flossing. In a letter to the AP, the US government acknowledged the effectiveness of flossing had never been researched. That seems not to be totally true, because AP looked at twenty-five studies comparing combinations of various toothbrushes and floss and found that the evidence for flossing is "weak, very unreliable," of "very low" quality, and carries "a moderate to large potential for bias."

Even if you decide to continue to continue to floss for now, you are right to question which type of floss to use, for both your health and that of the environment and the rest of civilization.

Some dental floss is made from nylon, a synthetic fiber derived from petroleum products. Petroleum is a non-sustainable resource, the extraction and production of which has had major detrimental impacts on the soil, ground water, surface water, and ecosystems. Nylon takes about fifty years to break down in the environment, and discarded floss (especially when it’s thrown in the toilet) can clog sewers, pollute lakes, and harm wildlife. Floss is also often coated with a petroleum-based wax. Americans buy over three million miles of dental floss every year, so this is substantial damage.

Floss made from polytetrafluoroethylene (PTFE) is becoming increasingly popular – and is marketed to dental offices to be given out to clients. Many people like it because it doesn’t shred and is easier to “glide” between tight teeth and around braces.

Other ingredients can be flavors and additives that vary with the manufacturer and can include fluoride. The summary of one dental floss patent reads: “Porous, high strength (PTFE) dental floss is coated with micro-crystalline wax. If desired, the floss may also incorporate one or more active tartar control, anticaries, antiplaque and/or antibacterial actives and/or dentally acceptable agents such as polishing and abrasive agents, coolants, flavorants and/or coagulants.”

Those can all be problematic for our health, but PTFE is the biggest problem, in my opinion. It also provides the coating in non-stick cookware, under its DuPont trade name Teflon. Although the main concern over Teflon has been the release of toxins when cookware is overheated, a chemical used in its manufacture, called perfluorooctanoic acid (PFOA), creates other problems. PTFE belongs to a class of perfluorochemicals (PFCs), which have become global pollutants in a short period of time. They have been found in our cities, on remote islands, in forests, and in polar regions, showing up in drinking water and wildlife.

Studies also show that nearly all people, regardless of age, have some PFCs in their blood. They have been found in samples of human breast milk, and in the blood of newborns. 

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Valve Seats

The valve seat in an internal combustion gasoline or diesel engine is the surface against which an intake or an exhaust valve rests during the portion of the engine operating cycle when that valve is closed. The valve seat is a critical component of an engine in that if it is improperly positioned, oriented, or formed during manufacture, valve leakage will occur which will adversely affect the engine compression ratio and therefore the engine efficiency, performance (power and torque), exhaust emissions, and engine life.

Valve seats are often formed by first press-fitting an approximately cylindrical piece of a hardened metal alloy, such as Stellite, into a cast depression in a cylinder head above each eventual valve stem position, and then machining a conical-section surface into the valve seat that will mate with a corresponding conical-section of the corresponding valve. Generally two conical-section surfaces, one with a wider cone angle and one with a narrower cone-angle, are machined above and below the actual mating surface, to form the mating surface to the proper width (called "narrowing" the seat), and to enable it to be properly located with respect to the (wider) mating surface of the valve, so as to provide good sealing and heat transfer, when the valve is closed, and to provide good gas-flow characteristics through the valve, when it is opened.

Inexpensive engines may have valve seats that are simply cut into the material of the cylinder head or engine block (depending on the design of the engine). Some newer engines have seats that are sprayed on rather than being pressed into the head, allowing them to be thinner, creating more efficient transfer of heat through the valve seats, and enabling the valve stems to function at a lower temperature, thus allowing the valve stems (and other parts of the valvetrain) to be thinner and lighter.

There are several ways in which a valve seat may be improperly positioned or machined. These include incomplete seating during the press fitting-step, distortion of the nominally circular valve seat surfaces such they deviate unacceptably from perfect roundness or waviness, tilt of the machined surfaces relative to the valve guide hole axis, deviation of the valve seat surfaces from concentricity with the valve guide holes, and deviation of the machined conical section of the valve seat from the cone angle that is required to match the valve surface. Automated quality control of inserted and machined valve seats has traditionally been very difficult to achieve until the advent of digital holography which has enabled high-definition metrology for measuring all of these listed deviations.

PTFE Encapsulated O-Rings

Encapsulated o-rings are o-rings consisting of a seamless and uniform Teflon encapsulation which completely encloses a rubber core material. Elastomer/rubber core material are a choice of Silicone or Viton. The combination of  these components creates an o-ring that is virtually chemically inert and compression set resistant for use in harsh sealing environments. This combination of chemically resistant polymer jacket over a low-compression set elastomer provides unique properties for a range of demanding applications

PTFE Encapsulated o-rings are o-rings consisting of a seamless and uniform PTFE FEP/PFA encapsulation/jacket which completely encloses a core material Viton® fluoroelastomer (also available in silicone). The combination of these components creates an o-ring that is virtually chemically inert and compression set resistant for use in harsh sealing environments. Encapsulated o-rings will decrease downtime and hence increase profitability wherever corrosive fluids and gases cause premature seal failure.

The PTFE provides a non stick surface for easy cleanup of viscous materials. These o-rings have a low coefficient of friction of .2 on metal and the o-rings surface is self lubricating. The PTFE encapsulation makes the o-rings sanitary by eliminating contamination of fluids by the elastomers. The o-rings are sterilizable and autoclavable, FDA compliant, USP Class VI compliant, NSF compliance available for specific applications.

Encapsulated o-rings are specifically designed to address the problem of sealing the most hostile chemicals and extreme temperature applications. Encapsulated o-rings consist of a solid or hollow elastomeric core encapsulated in a PTFE FEP or PFA sheath. The elastomeric core may be fluorocarbon or silicon rubber. Solid core encapsulated o-rings are generally used in static applications. Hollow Silicone core encapsulated o-rings are commonly used in applications where lower sealing force is required as in semi dynamic applications. The encapsulated o-ring offers an effective solution for many difficult applications. The PTFE FEP or PFA encapsulation actually affects the seal and the elastomeric core insures consistent compression on the seal. The result is an overall sealing compression, increasing with medium pressure. The encapsulated o-ring behaves like a highly viscous fluid, any pressure exerted on the seal is transmitted in all directions. Maximum operating temperature for FEP is 205°C (400°F) and for PFA 260°C (500°F).

Benefits

* Excellent chemical resistance
* Temperature range
  - silicone core: -75°F to 400°F (-60°C to 205°C)
  - flurocarbon core: 5°F to 440°F (-15°C to 205°C)
  - special applications are possible up to 500°F (260°C)
* Overall hardness 85° Shore A ± 5 durometer
* Sterilizable.
* Pressures from vacuum to 10000 psi (700 bar, 70 MPa)
* Low compression set characteristics.
* Anti-adhesive properties, non stick surface, low coefficient of friction
* FDA compliant
* No restrictions on inside diameter

Stainless Steel Braided PTFE Fuel Hose Line

Application:Racing fuel, pump gas, fuels with ethanol, alcohol based fuels, motor oil & coolant et

Pressure Rating: 1000 Working PSI / 5000 Burst PSI

Temperature Rating: -100F to 500F (-73°C to + 260°C) under most operating conditions.

Application: fuel, lube, alcohol, ethanol, coolant and air for automobiles or marine engines, most suitable for racing cars & motor racing bikes.

Fitments: These fuel hose and fittings are sized correctly 

PRODUCT FEATURES

This Braided Stainless Steel Fuel Hose are specially designed to work in any automotive project.

This hose provides you with unsurpassed levels of performance and reliability for your tough performance applications. This hose is ideal for high temperature, high pressure, and offers wide range of fluid compatibility.

This hose is made of high-quality Polyurethane on the inside that gives them high chemical and heat resistance, along with a braided stainless steel outside which gives them high durability, extreme pressure resistance, and a professional and high-tech appearance. They are smooth bore for optimal flow.

Polyurethane is flexible and strong and when combined with stainless steel braid can perform under high pressure and continuous flexing and vibration conditions.

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Plastic Welding Type

Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat (except solvent welding). Welding of thermoplastics is accomplished in three sequential stages, namely surface preparation, application of heat and pressure, and cooling. 

Hot gas welding

Hot gas welding, also known as hot air welding, is a plastic welding technique using heat. A specially designed heat gun, called a hot air welder, produces a jet of hot air that softens both the parts to be joined and a plastic filler rod, all of which must be of the same or a very similar plastic. (Welding PVC to acrylic is an exception to this rule.)

Hot air/gas welding is a common fabrication technique for manufacturing smaller items such as chemical tanks, water tanks, heat exchangers, and plumbing fittings.

In the case of webs and films a filler rod may not be used. Two sheets of plastic are heated via a hot gas (or a heating element) and then rolled together. This is a quick welding process and can be performed continuously.

Speed tip welding

With speed welding, the plastic welder, similar to a soldering iron in appearance and wattage, is fitted with a feed tube for the plastic weld rod. The speed tip heats the rod and the substrate, while at the same time it presses the molten weld rod into position. A bead of softened plastic is laid into the joint, and the parts and weld rod fuse. With some types of plastic such as polypropylene, the melted welding rod must be "mixed" with the semi-melted base material being fabricated or repaired. These welding techniques have been improved over time and have been utilized for over 50 years by professional plastic fabricators and repairers internationally. Speed tip welding method is a much faster welding technique and with practice can be used in tight corners. A version of the speed tip "gun" is essentially a soldering iron with a broad, flat tip that can be used to melt the weld joint and filler material to create a bond.

Extrusion welding

Extrusion welding allows the application of bigger welds in a single weld pass. It is the preferred technique for joining material over 6 mm thick. Welding rod is drawn into a miniature hand held plastic extruder, plasticized, and forced out of the extruder against the parts being joined, which are softened with a jet of hot air to allow bonding to take place.

Contact welding

This is the same as spot welding except that heat is supplied with thermal conduction of the pincher tips instead of electrical conduction. Two plastic parts are brought together where heated tips pinch them, melting and joining the parts in the process.

Hot plate welding

Related to contact welding, this technique is used to weld larger parts, or parts that have a complex weld joint geometry. The two parts to be welded are placed in the tooling attached to the two opposing platens of a press. A hot plate, with a shape that matches the weld joint geometry of the parts to be welded, is moved in position between the two parts. The two opposing platens move the parts into contact with the hot plate until the heat softens the interfaces to the melting point of the plastic. When this condition is achieved the hot plate is removed, and the parts are pressed together and held until the weld joint cools and re-solidifies to create a permanent bond.

Hot-plate welding equipment is typically controlled pneumatically, hydraulically, or electrically with servo motors.

This process is used to weld automotive under hood components, automotive interior trim components, medical filtration devices, consumer appliance components, and other car interior components.

High frequency welding

High Frequency welding, also known as Dielectric Sealing or Radio Frequency (R.F.) Heat Sealing is a very mature technology that has been around since the 1940s. High frequency electromagnetic waves in the range of Radio Frequencies can heat certain polymers up to softening the plastics for joining. Heated plastics, under pressure weld together. Heat is generated within the polymer by the rapid reorientation of some chemicals dipoles of the polymer, which means that the heating can be localized, and the process can be continuous.

Induction welding

When an electrical insulator, like a plastic, is embedded with a material having high electrical conductivity, like metals or carbon fibers, induction welding can be performed. The welding apparatus contains an induction coil that is energised with a radio-frequency electric current. This generates an electromagnetic field that acts on either an electrically conductive or a ferromagnetic workpiece. In an electrically conductive workpiece, the main heating effect is resistive heating, which is due to induced currents called eddy currents. Induction welding of carbon fiber reinforced thermoplastic materials is a technology commonly used in for instance the aerospace industry.

In a ferromagnetic workpiece, plastics can be induction-welded by formulating them with metallic or ferromagnetic compounds, called susceptors. These susceptors absorb electromagnetic energy from an induction coil, become hot, and lose their heat energy to the surrounding material by thermal conduction.

Injection welding

Injection welding is similar/identical to extrusion welding, except, using certain tips on the handheld welder, one can insert the tip into plastic defect holes of various sizes and patch them from the inside out. The advantage is that no access is needed to the rear of the defect hole. The alternative is a patch, except that the patch can not be sanded flush with the original surrounding plastic to the same thickness. PE and PP are most suitable for this type of process. The Drader injectiweld is an example of such tool.

Ultrasonic welding

In ultrasonic welding, high frequency (15 kHz to 40 kHz) low amplitude vibration is used to create heat by way of friction between the materials to be joined. The interface of the two parts is specially designed to concentrate the energy for the maximum weld strength. Ultrasonic can be used on almost all plastic material. It is the fastest heat sealing technology available.

Friction welding

In friction welding, the two parts to be assembled are rubbed together at a lower frequency (typically 100–300 Hz) and higher amplitude (typically 1 to 2 mm (0.039 to 0.079 in)) than ultrasonic welding. The friction caused by the motion combined with the clamping pressure between the two parts creates the heat which begins to melt the contact areas between the two parts. At this point, the plasticized materials begin to form layers that intertwine with one another, which therefore results in a strong weld. At the completion of the vibration motion, the parts remain held together until the weld joint cools and the melted plastic re-solidifies. The friction movement can be linear or orbital, and the joint design of the two parts has to allow this movement.

Spin welding

Spin welding is a particular form of frictional welding. With this process, one component with a round weld joint is held stationary, while a mating component is rotated at high speed and pressed against the stationary component. The rotational friction between the two components generates heat. Once the joining surfaces reach a semi-molten state, the spinning component is stopped abruptly. Force on the two components is maintained until the weld joint cools and re-solidifies. This is a common way of producing low- and medium-duty plastic wheels, e.g., for toys, shopping carts, recycling bins, etc. This process is also used to weld various port openings into automotive under hood components.

Laser welding

This technique requires one part to be transmissive to a laser beam and either the other part absorptive or a coating at the interface to be absorptive to the beam. The two parts are put under pressure while the laser beam moves along the joining line. The beam passes through the first part and is absorbed by the other one or the coating to generate enough heat to soften the interface creating a permanent weld.

Semiconductor diode lasers are typically used in plastic welding. Wavelengths in the range of 808 nm to 980 nm can be used to join various plastic material combinations. Power levels from less than 1W to 100W are needed depending on the materials, thickness and desired process speed.\

Solvent welding

In solvent welding, a solvent is applied which can temporarily dissolve the polymer at room temperature. When this occurs, the polymer chains are free to move in the liquid and can mingle with other similarly dissolved chains in the other component. Given sufficient time, the solvent will permeate through the polymer and out into the environment, so that the chains lose their mobility. This leaves a solid mass of entangled polymer chains which constitutes a solvent weld.

This technique is commonly used for connecting PVC and ABS pipe, as in household plumbing. The "gluing" together of plastic (polycarbonate, polystyrene or ABS) models is also a solvent welding process.

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Polymer Adsorption Applications

Adsorption is the adhesion of ions or molecules onto the surface of another phase. Adsorption may occur via physisorption and chemisorption. Ions and molecules can adsorb to many types of surfaces including polymer surfaces. A polymer is a large molecule composed of repeating subunits bound together by covalent bonds. The adsorption of ions and molecules to polymer surfaces plays a role in many applications including: biomedical, structural, and coatings.

Implant Coatings

Protein-resistant coatings:Protein adsorption influences the interactions that occur at the tissue-implant interface. Protein adsorption can lead to blood clots, the foreign-body response and ultimately the degradation of the device. In order to counter-act the effects of protein adsorption, implants are often coated with a polymer coating to decrease protein adsorption.

Polyethylene glycol (PEG) coatings have been shown to minimize protein adsorption in the body. The PEG coating consists of hydrophilic molecules that are repulsive to protein adsorption. Proteins consist of hydrophobic molecules and charge sites that want to bind to other hydrophobic molecules and oppositely charged sites. By applying a thin monolayer coating of PEG, protein adsorption is prevented at the device site. Furthermore, the device’s resistance to protein adsorption, fibroblast adhesion and bacteria adhesion are increased.

Antithrombogenic coatings:The hemocompatability of a medical device is dependent upon surface charge, energy and topography. Devices that fail to be hemocompatabile run the risk of forming a thrombus, proliferation and compromising the immune system. Polymer coatings are applied to devices to increase their hemocompatability. Chemical cascades lead to the formation of fibrous clots. By choosing to use hydrophilic polymer coatings, protein adsorption decreases and the chance of negative interactions with the blood diminishes as well. One such polymer coating that increases hemocompatability is heparin. Heparin is a polymer coating that interacts with thrombin to prevent coagulation. Heparin has been shown to suppress platelet adhesion, complement activation and protein adsorption.

Structural

Advanced polymer composites:Advanced polymer composites are used in the strengthening and rehabilitation of old structures. These advanced composites can be made using many different methods including prepreg, resin, infusion, filament winding and pultrusion. Advanced polymer composites are used in many airplane structures and their largest market is in aerospace and defense.

Fiber reinforced polymers:Fiber-reinforced polymers (FRP) are commonly used by civil engineers in their structures. FRPs respond linear-elastically to axial stress, making them a great material to hold a load. FRPs are usually in a laminate formation with each lamina having unidirectional fibers, typically carbon or glass, embedded within a layer of light polymer matrix material. FRPs have great resistance against environmental exposure and great durability.

Polytetrafluoroethylene:Polytetrafluoroethylene (PTFE) is a polymer used in many applications including non-stick coatings, beauty products, and lubricants. PTFE is a hydrophobic molecule composed of carbon and fluorine. Carbon-fluorine bonds cause PTFE to be a low-friction material, conducive in high temperature environments and resistant to stress cracking. These properties cause PTFE to be non-reactive and used in a wide array of applications.

Polymer adsorption in porous media:Physical adsorption and mechanical entrapment are two major causes of polymer retention in porous media. Low polymer retention in the reservoir is essential to the success of a polymer EOR operation. 

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Common thermoplastic materials - thermosoftening plastic

A thermoplastic, or thermosoftening plastic, is a plastic material, a polymer, that becomes pliable or moldable above a specific temperature and solidifies upon cooling.

Most thermoplastics have a high molecular weight. The polymer chains associate through intermolecular forces, which weaken rapidly with increased temperature, yielding a viscous liquid. Thus, thermoplastics may be reshaped by heating and are typically used to produce parts by various polymer processing techniques such as injection molding, compression molding, calendering, and extrusion. Thermoplastics differ from thermosetting polymers, which form irreversible chemical bonds during the curing process. Thermosets do not melt when heated: they decompose and do not reform upon cooling.

Acrylic:Acrylic, a polymer called poly (PMMA), is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a sturdy substitute for glass for items such as aquariums, motorcycle helmet visors, aircraft windows, viewing ports of submersibles, and lenses of exterior lights of automobiles. It is extensively used to make signs, including lettering and logos. In medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water.

ABS:Acrylonitrile butadiene styrene (ABS) is a terpolymer synthesized from styrene and acrylonitrile in the presence of polybutadiene. ABS is a light-weight material that exhibits high impact resistance and mechanical toughness. It poses few risks to human health under normal handling. It is used in many consumer products, such as toys, appliances, and telephones.

Nylon:Nylon belongs to a class of polymers called polyamides. It has served as a substitute mainly for hemp, cotton and silk, in products such as parachutes, cords, sails, flak vests and women's clothing. Nylon fibers are useful in making fabrics, rope, carpets and musical strings, whereas in bulk form, Nylon is used for mechanical parts including machine screws, gears and power tool casings. In addition, it is used in the manufacture of heat-resistant composite materials.

PLA:Polylactic acid (polylactide) is a biodegradable thermoplastic aliphatic polyester derived from renewable resources, such as corn starch (in the United States), tapioca roots, chips or starch (mostly in Asia), or sugarcane. It is one of the materials used for 3D printing with fused deposition modeling (FDM) techniques.

Polybenzimidazole:Polybenzimidazole fiber is a synthetic fiber with a very high melting point. It has exceptional thermal and chemical stability and does not readily ignite. It was first discovered by American polymer chemist Carl Shipp Marvel in the pursuit of new materials with superior stability, retention of stiffness, toughness at elevated temperature. Due to its high stability, Polybenzimidazole is used to fabricate high-performance protective apparel such as firefighter’s gear, astronaut space suits, high temperature protective gloves, welders’ apparel and aircraft wall fabrics. In recent years, polybenzimidazole found its application as membrane in fuel cells.

Polycarbonate:Polycarbonate (PC) thermoplastics are known under trademarks such as Lexan, Makrolon, Makroclear, and arcoPlus. They are easily worked, molded, and thermoformed for many applications, such as electronic components, construction materials, data storage devices, automotive and aircraft parts, check sockets in prosthetics, and security glazing. Polycarbonates do not have a unique resin identification code. Items made from polycarbonate can contain the precursor monomer bisphenol A (BPA).

Polyether sulfone:Polyether sulfone (PES) is a class of specially engineered thermoplastics with high thermal, oxidative, and hydrolytic stability, and good resistance to aqueous mineral acids, alkalis, salt solutions, oils and greases.

Polyoxymethylene:Polyoxymethylene (POM), also known as acetal, polyacetal and polyformaldehyde, is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and sold variously by such names as Delrin, Celcon, Ramtal, Duracon, Kepital and Hostaform.

Polyetherether ketone:Polyether ether ketone(PEEK) is a colourless organic thermoplastic polymer in the polyaryletherketone (PAEK) family, used in engineering applications. It was originally introduced by Victrex PLC, then ICI (Imperial Chemical Industries) in the early 1980s. It has attractive properties like good abrasion resistance, low flammability and emission of smoke and toxic gases.

Polyetherimide:Polyetherimide (PEI), produced by a novel nitro displacement reaction involving bisphenol A, 4, 4’-methylenedianiline and 3-nitrophthalic anhydride, has high heat distortion temperature, tensile strength and modulus. They are generally used in high performance electrical and electronic parts, microwave appliances, and under-the-hood automotive parts.

Polyethylene:Polyethylene (polyethene, polythene, PE) is a family of similar materials categorized according to their density and molecular structure.It is also known as poly and is obtained by the addition polymerisation of ethylene.It may be of low density or High density depending upon the process used in its manufacturing. It is resistant to moisture and most of the chemicals. It is flexible at room temperature. (and low temperature) and can be heat sealed.

Polyphenylene oxide:Polyphenylene oxide (PPO), which is obtained from the free-radical, step-growth oxidative coupling polymerization of 2,6-xylenol, has many attractive properties such as high heat distortion and impact strength, chemical stability to mineral and organic acids, and low water absorption. PPO is difficult to process, and hence the commercial resin (Noryl) is made by blending PPO with high-impact polystyrene (HIPS), which serves to reduce the processing temperature.

Polyphenylene sulfide:Polyphenylene sulfide (PPS) obtained by the condensation polymerization of p-dichlorobenzene and sodium sulfide, has outstanding chemical resistance, good electrical properties, excellent flame retardance, low coefficient of friction and high transparency to microwave radiation. PPS is principally used in coating applications. This is done by spraying an aqueous slurry of PPS particles and heating to temperatures above 370°C. Particular grades of PPS can be used in injection and compression molding at temperatures (300 to 370°C) at which PPS particles soften and undergo apparent crosslinking. Principal applications of injection and compression molded PPS include cookware, bearings, and pump parts for service in various corrosive environments.

Polypropylene:Polypropylene (PP) is useful for such diverse products as reusable plastic food containers, microwave- and dishwasher-safe plastic containers, diaper lining, sanitary pad lining and casing, ropes, carpets, plastic moldings, piping systems, car batteries, insulation for electrical cables and filters for gases and liquids. In medicine, it is used in hernia treatment and to make heat-resistant medical equipment. Polypropylene sheets are used for stationery folders and packaging and clear storage bins. Polypropylene is defined by the recyclable plastic number 5. Although relatively inert, it is vulnerable to ultraviolet radiation and can degrade considerably in direct sunlight. Polypropylene is not as impact-resistant as the polyethylenes (HDPE, LDPE). It is also somewhat permeable to highly volatile gases and liquids.

Polystyrene:Polystyrene is manufactured in various forms that have different applications. Extruded polystyrene (PS) is used in the manufacture of disposable cutlery, CD and DVD cases, plastic models of cars and boats, and smoke detector housings. Expanded polystyrene foam (EPS) is used in making insulation and packaging materials, such as the "peanuts" and molded foam used to cushion fragile products. Extruded polystyrene foam (XPS), known by the trade name Styrofoam, is used to make architectural models and drinking cups for heated beverages. Polystyrene copolymers are used in the manufacture of toys and product casings.

Polyvinyl chloride:Polyvinyl chloride (PVC) is a tough, lightweight material that is resistant to acids and bases. Much of it is used by the construction industry, such as for vinyl siding, drainpipes, gutters and roofing sheets. It is also converted to flexible forms with the addition of plasticizers, thereby making it useful for items such as hoses, tubing, electrical insulation, coats, jackets and upholstery. Flexible PVC is also used in inflatable products, such as water beds and pool toys. PVC is also a common material in vinyl action figures, especially in countries such as Japan, where the material is used extensively in so-called Sofubi figures. As PVC bends easily and has a tendency to be bent during transit, a method to 'repair' this deformation is to heat the plastic until it becomes mobile, then 're-bend' the material into the correct position.

Teflon:Teflon a brand name of DuPont for a variety of the polymer polytetrafluoroethylene (PTFE), which belongs to a class of thermoplastics

Source:https://www.sukoptfe.com/common-thermoplastic-materials-thermosoftening-plastic